Modeling Reservoir Storage Scenarios by Consensus

Volume 47 Issue 3 Symposium on New Mexico's Rio Grande Reservoirs

Summer 2007

Modeling Reservoir Storage Scenarios by Consensus Modeling Reservoir Storage Scenarios by Consensus

Susan Kelly

Recommended Citation Recommended Citation Susan Kelly, Modeling Reservoir Storage Scenarios by Consensus, 47 Nat. Resources J. 653 (2007). Available at: https://digitalrepository.unm.edu/nrj/vol47/iss3/8

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SUSAN KELLY*

Modeling Reservoir Storage Scenariosby Consensus

ABSTRACT

Computer modeling is a powerful scientific tool used to simulate thebehavior of systems under a variety of possible future scenarios.Many scientists are involved in simulating the Rio Grande invarious conditions, both natural and manmade. This articledescribes a collaborative process for developing simulations that canbe used to understand the probable effects of changed operations ofthe system of Rio Grande reservoirs. Participants learned that evendeveloping hypothetical model runs can be controversial. It wasdifficult to achieve consensus among a diverse group of interestedparties on how to model future scenarios for management of thereservoirs.

I. INTRODUCTION

In 2001, the Middle Rio Grande Endangered Species ActCollaborative Program (Collaborative Program), a group of federal, state,and local water management officials; Native American pueblos; and otherinterested parties, formed a water subcommittee to examine how toimprove water operations in New Mexico's Middle Rio Grande Valley.'Challenged to meet the water supply needs for two endangered species, thegroup attempted a preliminary analysis of alternative reservoir storagescenarios by testing the effects of various alternatives on the water supply.The group sought consensus on the details of several scenarios and plannedto use hydrologic modeling tools to test the viability of each. This articlefirst describes the background, the organization of the group, thegeographic setting and water supply regime, and the available modelingtools. The article then summarizes the process and the alternatives thatwere evaluated. In conclusion, it discusses the roadblocks created by theconsensus approach and the outcomes: a broader understanding of therespective positions of the parties, new ideas on potential improvements to

* Associate Director, The Utton Transboundary Resources Center, University of New

Mexico School of Law.1. The Middle Rio Grande Valley is defined as the stretch of river between Cochiti Lake

and Elephant Butte Reservoir. The broader Collaborative Program area is defined infra in PartII.E.

NATURAL RESOURCES JOURNAL

the water management system, and a commitment to support futurehydrologic modeling.

II. BACKGROUND

A. Endangered Species

The impact of the Endangered Species Act' (ESA) in the Middle RioGrande Valley of semi-arid New Mexico brought one of the most pressingenvironmental and water supply debates in the southwestern United States3

to the forefront. The Middle Rio Grande Valley is home to both the RioGrande silvery minnow (silvery minnow), listed as an endangered speciesin 1994, and the southwestern willow flycatcher (flycatcher), listed asendangered in 1995.

Over time, the silvery minnow's habitat had become concentratedin the middle reaches of the Rio Grande.* For centuries, the Middle RioGrande Valley was sparsely populated with native Pueblos and, later,Hispanic farming families. Today most of New Mexico's urbandevelopment is located in the Middle Rio Grande Valley. As Anglosettlement occurred, dams for irrigation and flood control were constructedand the silvery minnow was trapped or could no longer migrate. A riverthat had previously receded and gone dry during the frequent periods ofdrought had become a series of isolated reaches between dams. The declineof the silvery minnow has been attributed to modification of the flowregime, channel drying resulting from impoundments, water diversions foragriculture, stream channelization, predation by non-native fish, anddecreasing water quality.'

Another sign of the troubled ecology in the region occurred whencritical habitat for the flycatcher was designated in 2005 and included theMiddle Rio Grande Valley. Reduction or elimination of surface water dueto diversion and groundwater pumping are cited as major reasons for thedecline of flycatcher habitat.6

The water-related problems in the region, including its highlyvariable seasonal supply, the unquantified water rights of major water users

2. 16 U.S.C. §§ 1531-1544 (2000).3. U.S. BUREAU OF RECLAMATION, WATER 2025: PREVENTING CRISES AND CONFLICTS IN THE

WEST9 (2003), availableat http://ceres.ca.gov/biodiversity/Meetings/archive/water03/water2025.pdf.

4. The Reach of the River Between Cochiti Dam and Elephant Butte Reservoir, 68 Fed.Reg. 8088 (Feb. 19, 2003) (to be codified at 50 C.F.R. pt. 17).

5. Id.6. U.S. FISH & WILDLIFE SERV., FINAL RECOVERY PLAN: SOUTHWESTERN WILLOW

FLYCATCHER 66 (2002).

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MODELING RESERVOIR STORAGE

and six Indian Pueblos, thousands of individual water rights holders,interstate compact delivery obligations to Texas, and rapid populationgrowth, make compliance with the ESA extremely challenging. This wasparticularly true in 2004 while the work discussed in this article wasunderway due to extreme drought conditions. And, although progress hasbeen made, the challenges persist today.

In addition to (and in spite of) the myriad legal proceedings thatensued beginning in 1999,7 efforts have been ongoing in many differentvenues to develop strategies to address the needs of the silvery minnow andflycatcher without impacting valid water rights or Rio Grande Compactobligations. One of the most significant efforts was the formation of theCollaborative Program. Within the Program, the water subcommitteeattempted to examine one aspect of the problem -reservoir storage andoperations -with the objective that improving this important piece of thesystem would help achieve a sustainable water supply for endangeredspecies without harming other water users. This article is a report on thework of the subcommittee's Preliminary Reservoir Storage ModelingAnalysis (Preliminary Analysis) completed in 2005.8

B. Middle Rio Grande Endangered Species Act Collaborative Program

The Collaborative Program was formed to seek short- and long-term solutions to aid in the recovery of endangered species in the programarea in order to protect water users' plans from the legal obligations of thefederal government to protect endangered species. One of the goals of theCollaborative Program is to develop and exercise creative and flexibleoptions under the ESA so that water use and development can proceed incompliance with applicable state and federal laws.

At the time of the Preliminary Analysis (2004/2005), theCollaborative Program provided a venue for many agencies and interestgroups to talk with one another about river management concerns. It wascomprised of federal, tribal, state, and local governments, as well as non-governmental organizations and universities. Today, with significant

7. See Susan Kelly, Summary of Minnow Litigation Through July 2005, in PreliminaryReservoir Storage Modeling Analysis (Attachment D), in THE MIDDLE Rio GRANDE ENDANGEREDSPECIES ACT COLLABORATWE PROGRAM WATER PLAN D-17 (2005), available at http://uttoncenter.unm.edu/pdfs/Preliminary%20_- Analysis_12-15-05 final.pdf; Joan E. Drake, Contractual Dis-cretion and the Endangered Species Act: Can the Bureau of Reclamation Reallocate Federal ProjectWater for Endangered Species in the Middle Rio Grande?, 41 NAT. RESOURCES J. 487, 498 (2001);Lara Katz, A History of the Minnow Litigation and Its Implications for the Future of ReservoirOperations on the Rio Grande, 47 NAT. RESORCESJ. 675 (2007); Letty Belin, Water Managementin the Middle Rio Grande, NM STATE BAR BULL., Oct. 2, 2003, at 7.

8. Kelly, supra note 7, at D-8.

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funding from Congress, the Program continues to support projects thatbenefit the silvery minnow and the flycatcher in habitat restoration,scientific understanding of the needs of the species, and water supply andmanagement.9

C. Water Acquisition and Management Subcommittee

The Water Acquisition and Management Subcommittee of theCollaborative Program (WAM) was formed to address how to obtainsufficient water and adjust operations to meet the minimum flow targets ofthe silvery minnow and the habitat needs of the flycatcher. ° Most of themany Program participants had a representative on the WAM sub-committee, which functioned under the direction of the Program's SteeringCommittee." The subcommittee's mission was to evaluate water acquisitionand management opportunities to support the goals of the Program.WAM's objectives included researching, developing, evaluating, and imple-menting water management alternatives; examining ideas for efficientwater use; and finding strategies to offset depletions caused by programactivities (the latter essentially referring to situations where program-sponsored habitat restoration projects might require additional water).Many members of WAM felt it was important to address reservoir storageand operations (especially focusing on gaining long-term flexibility inreservoir storage) because they are important components of watermanagement and supply.

In addition to reservoir storage, the annual renewable water supplywas an overwhelming issue for WAM as a result of the drought conditionsin 2004. Agencies were concerned with meeting the flow targets in effect forthe ten-year Biological Opinion for the silvery minnow and flycatcher. Tothis end, WAM initiated and funded many activities: the installation ofgages for quantifying water flow, diversions, and return flows; thedevelopment of a decision support system for rotational delivery ofirrigation water in the Middle Rio Grande Conservancy District (MRGCD);

9. Middle Rio Grande Endangered Species Act Collaborative Program, http://www.fws.gov/mrgesacp/index.cfm (last visited July 25,2007).

10. See generally Executive Committee, Summary of Draft Long-Term Water Acquisition andManagement Plan, in MIDDLE RIOGRANDE ENDANGERED SPECIES AcT COLLABORATIVE PROGRAM,LONG-TERM PLAN 2005-2014 app. at B-1 (2006), available at http://www.fws.gov/mrgesacp/pdf/Final LTP 11-13-06.pdf; see also WATERAcQulrsIIONS& MGMT. SUBCOMM., FINALREPORT,MRGESA COLLABORATIVE PROGRAM LONG-TERM WATER AcQUISITIONS AND ADAPTIVE WATER

MANAGEMENT PLAN § 1.2, at 2 (Nov. 28, 2005, and Dec. 15, 2005 Update) [hereinafter FINALREPORT] (on file with Natural Resources Journal).

11. Middle Rio Grande Endangered Species Act Collaborative Program, 2003 AnnualReport, supra note 9, at 7.

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the creation of a water demand budget; and research on many potentialactions directed toward meeting the water needs of the Program.

D. Concept of the Preliminary Analysis

The Water Subcommittee's Preliminary Analysis attempted todevelop, by consensus, a range of storage alternatives to be objectivelyevaluated using an agreed-upon modeling tool. The long-term goal was topropose institutional changes that would allow the Middle Rio GrandeValley to optimize its water supply and take advantage of storage flexibilityin wet years. If the preliminary analysis of alternatives demonstratedpotential water savings, WAM anticipated making further recommenda-tions on productive directions for the Collaborative Program to pursue. Thesubcommittee anticipated recommendations that might include program-sponsored studies to more fully evaluate reservoir authorizations andoperations; structured negotiations between critical stakeholders; and moredetailed development of the legal, political, and environmental issuesassociated with alternative reservoir management scenarios. The benefit tothe Collaborative Program was to potentially improve management of thewater storage system and minimize the need for costly acquisition ofsupplemental water. 2 It was understood that the analysis was preliminary -significant further work would be necessary in order to achieve optimalreservoir management.

The variety of interests in the waters of the Rio Grande and itsreservoirs required broad representation in developing the PreliminaryAnalysis. The Program represented the diverse interests more comprehen-sively than any other forum at the time. Participation was open to anyinterest group that chose to participate.13 The Preliminary Analysis pro-vided a good venue for Middle Rio Grande water interests to look jointlyat the reservoir storage system and its constraints and to determine if theregion could collectively manage the river's reservoirs more effectively andefficiently by creatively working together. WAM partnered with the UttonTransboundary Resources Center1 4 to undertake the Preliminary Analysis.

12. At the present time, San Juan-Chama (SJC) water is the primary source of wateravailable for lease to the Collaborative Program. This water is expected to decrease over timeas the SJC contractors begin to use it. Executive Committee, supra note 10, at B-3 n.1.

13. The members of WAM representing Program signatories were usually watermanagers, technical experts, or water resource professionals and thus were well suited toprovide the expertise to develop and evaluate scenarios.

14. The Utton Center, housed at the University of New Mexico School of Law, is chargedwith carrying on the work of the late Professor Albert E. Utton to promote equitable andsustainable management and the utilization of transboundary resources. See The UttonTransboundary Resources Center, http://uttoncenter.unm.edu/ (last visited July 25, 2007).

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The reservoirs in the Middle Rio Grande Valley were authorized byfederal legislation that governs the volume of water the Middle Rio Grandecan expect to store in the future, depending upon climatic conditions. Thereare many factors that constrain the operations of the reservoirs, includingphysical and legal limitations on storage space; congressional authoriza-tions; international treaty and Rio Grande Compact obligations; and themany competing water rights demands. WAM previously developed apaper as part of its long-term plan entitled, Storage and Management ofProgram Water.5 As described in that paper, the Program area had a limitedamount of physical water storage capacity in reservoirs that could beutilized by the Program.

E. The Geographic Setting

The Collaborative Program area encompasses the headwaters of theRio Chama Watershed and the Rio Grande, including tributaries, from theNew Mexico-Colorado state line downstream to the 4,450 foot elevationspillway crest of Elephant Butte Dam. 6 The area contains land within manycounties and cities in New Mexico as well as land within 18 Indian Pueblosand one Indian Nation. The average annual precipitation in the Programarea is between 7 and 15 inches. In the high mountain areas, precipitation,much in the form of snow pack, exceeds 25 inches a year.17 The watersupply for the region comes from the natural flow of the Rio Grande and itstributaries and from transbasin diversions from the San Juan-Chamaproject, which imports water from the Colorado River Basin. In addition,there is significant reliance on ground water, primarily for municipal use.

The Utton Center offers impartial expertise and scholarship in examining and analyzingproblems from a multidisciplinary standpoint. Although the University of New Mexico wassignatory to the Program in 2004-2005, it did not have a direct stake in the outcome of thedecisions to be made regarding Collaborative Program water supply. Thus, the Utton Centerwas able to act as a neutral party to assist in organizing and furthering the PreliminaryAnalysis. The Utton Center provided support to the process, scheduling meetings, developingand distributing scenarios, documenting meetings, providing progress reports, andcoordinating among various stakeholders. Dick Kreiner, former co-Chair of WAM and retiredProject Manager with the Corps of Engineers, was an integral part of the project.

15. Mark Yuska, Nancy Purdy & Dick Kreiner, Draft Position Paper, Storage and Manage-ment of Program Water (Nov. 7, 2003), available at http://www.fws.gov/mrgesacp/pdf/StoragePositionPaper8.110603.pdf.

16. Memorandum of Understanding, Middle Rio Grande Endangered Species ActCollaborative Program 1 n.1 (2002), available at http://www.usbr.gov/uc/albuq/rm/mrg/collab/final-mou.pdf.

17. U.S. Army Corps of Eng'rs, Upper Rio Grande Water Operations Model: Upper RioGrande Basin, http://www.spa.usace.army.mil/urgwom/aboutthe.asp (last visited July 22,2007).

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The majority of the surface water comes from snowmelt. The springrunoff usually begins in April and may continue through June andsometimes into July for high snow pack years. At the Otowi Bridge, whereNew Mexico's upper index Compact gage is located, the Rio Grande'saverage annual flow is 1.1 million acre-feet. At San Marcial, above ElephantButte, at the downstream end of the Middle Rio Grande Valley, the averageannual flow is 923,000 acre-feet. Generally, the Rio Grande gains waterabove Otowi and loses water below Otowi. During the summer months,precipitation from thunderstorms may be a significant contributor tostreamflow for short durations and many of the Rio Grande's largesttributaries in the Middle Rio Grande usually flow in response to theseevents. These tributaries include the Tijeras Arroyo, Rio Salado, Rio Puerco,and Rio Jemez (although the Rio Jemez may more frequently havesnowmelt runoff). The greatest flood-producing storms usually occurbetween March and May and September and October.18

F. Overview of Reservoirs

The Bureau of Reclamation's (BOR) San Juan-Chama (SJC) Projectis a transbasin diversion system that imports water from tributaries of theSan Juan River to supplement the native flow of the Rio Grande. This iswater that would otherwise flow to the Colorado River. The water isdelivered through the Azotea Tunnel that runs under the ContinentalDivide to Willow Creek. Heron Reservoir was constructed in 1971 as partof the SJC Project on Willow Creek. Willow Creek delivers SJC water to theRio Chama, which then empties into the Rio Grande. The project hasannually imported an average of 94,200 acre-feet since diversions wereinitiated. This water is not included in accounting under the Rio GrandeCompact. The SJC water is primarily intended for municipal/ industrial andagricultural uses.

El Vado Reservoir is the next reservoir below Heron and was builtas part of the MRGCD works in 1935. El Vado is primarily used to storenative Rio Chama flows for use by the MRGCD for irrigation. It is alsowhere the BOR stores prior and paramount water for the Six Middle RioGrande Pueblos.

Abiquiu Reservoir sits downstream from El Vado on the RioChama, about 30 miles upstream of its confluence with the Rio Grande. Thisreservoir was built in 1962 by the U.S. Army Corps of Engineers (Corps)with legislative authorization to control floods and sediment. In 1981,Congress amended the authorizing legislation to allow storage of SJC water.

18. Id.

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Below Abiquiu is Cochiti Lake-the only reservoir in the Middle RioGrande Valley on the main stem of the Rio Grande. Cochiti Dam was builtto protect the City of Albuquerque from flooding. The original authoriza-tion was for flood and sediment control purposes, but authorizinglegislation was added in 1964 to provide a recreational pool, and 5,000 acre-feet per year of SJC water was allocated for this purpose.

Elephant Butte Reservoir, located at the southern end of the MiddleRio Grande Valley, is where New Mexico's Compact water is delivered toTexas. About 57 percent of the water delivered to "Texas" under theCompact is actually delivered to southern New Mexico farmers.

G. Overview of Rio Grande Compact

The Rio Grande Compact (Compact)19 is an agreement betweenTexas, New Mexico, and Colorado apportioning the waters of the RioGrande above Ft. Quitman, Texas. New Mexico's annual water allocationavailable for use within the Middle Rio Grande is a maximum of 405,000acre-feet of the flow of the Rio Grande as determined based upon themeasurement at the Otowi index gage located just upstream of CochitiLake. New Mexico's deliveries are measured as the releases from ElephantButte Dam plus the change in storage in Elephant Butte; thus, theevaporation loss is counted against New Mexico's Compact allocation. NewMexico is allowed to consume all of the tributary inflows into the RioGrande between the Otowi gage and Elephant Butte. The Compact requiresannual water accounting and provides for a system of annual debits andcredits based on a calendar year. Water must be retained in storage inreservoirs constructed after 1929 to the extent of each state's debits andcannot be used. It must be released upon demand of the downstream state.Article VII of the Compact provides that, if usable storage in Elephant Butteand Caballo Reservoirs2' is less than 400,000 acre-feet, neither Colorado norNew Mexico may increase the amount of water stored in upstream reservoirsconstructed after 1929. Water imported from the Colorado River Basin, inparticular the San Juan-Chama water supply, is not subject to the Rio GrandeCompact apportionment. The Compact does not affect the obligations of theUnited States to Indian tribes or impair Indian water rights.

H. Water Uses - Demands and Projected Trends

Agricultural irrigation is the largest use of surface water in theProgram area. It is estimated to account for approximately 40 percent of the

19. Rio Grande Compact, N.M. STAT. § 72-15-23 (1978).20. Caballo Reservoir is approximately 20 miles south of Elephant Butte Reservoir and is

operated in tandem with Elephant Butte.

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water used in the Middle Rio Grande Valley. This figure does not includeevaporative losses on water stored for agricultural purposes, which isapproximately 20 percent of the water categorized as evaporative loss.21 Thelargest area of evaporative loss is at Elephant Butte Reservoir.

The consumption of surface water for municipal and industrialpurposes is less than for agricultural purposes, but in the Middle RioGrande Valley municipal and industrial water use is a larger proportion ofconsumptive water use than in other parts of New Mexico. Municipal andindustrial use is currently estimated to be approximately seven percent ofwater used in the Middle Rio Grande Valley. This number will increase aspopulation grows and the delayed effects of groundwater pumping reachthe river. Another major component of consumptive water use in theMiddle Rio Grande occurs in the riparian zone. Riparian consumption bytrees and other vegetation and river and soil evaporation is estimated to beapproximately 37 percent of the usage in the Middle Rio Grande Valley.

The Preliminary Analysis focused primarily on the evaporative losscomponent of water depletion in the Middle Rio Grande Valley. In ElephantButte, evaporative loss is estimated to range between 50,000 and 250,000acre-feet per year, depending upon the quantity stored, temperature, wind,etc.22 Water savings could occur by moving or holding some of this storedwater in upstream reservoirs where the evaporative loss is significantly less.WAM also wanted to explore opportunities for changed operations, i.e.,different release schedules that could provide water in the river whenneeded for Program purposes.

I. Upper Rio Grande Water Operations Model

The Upper Rio Grande Water Operations Model (URGWOM) is acomputer model that is capable of simulating water storage and deliveryoperations in the Rio Grande from its headwaters in Colorado to belowCaballo Dam in New Mexico. Its purpose is to model flood controloperations and facilitate water accounting and planning for wateroperations alternatives. URGWOM is a cooperative effort of six federalagencies' that began in 1996 and is led by the Corps. A vast amount of datahas been developed and stored in the URGWOM database since 1996. Thedata include climatic conditions, riparian evapotranspiration, evaporativelosses at reservoirs, evaporative losses on river reaches, seepage, water

21. S.S. PAPADOPULOS & Assocs., INC., MIDDLE Rio GRANDE WATER SUPPLY STUDY, at ES-4(2000), available at http://www.ose.state.nm.us/water-info/mrgwss/mrgwss-final-rpt.pdf.

22. Id. at 25.23. The Bureau of Reclamation, the U.S. Fish and Wildlife Service, the U.S. Geological

Survey, the Bureau of Indian Affairs, the International Boundary and Water Commission (U.S.Section), and the U.S. Army Corps of Engineers.

Summ-er 2007]


operations, water usage, snowmelt runoff, and thousands of other pieces ofinformation related to the hydrology of the Upper Rio Grande watershed.

One difficulty in using the model at the time of the PreliminaryAnalysis was URGWOM's level of accuracy in quantifying gains and lossesafter discrete quantities of water are released from reservoirs. In the 2004 to2005 time frame, gains and losses were difficult to estimate accurately in theMiddle Rio Grande Valley, especially during low flow conditions. Furtherdata collection was needed, particularly regarding the connection betweenshallow groundwater and river flows. It would take time to obtain andintegrate these data into the model. WAM saw the importance of continuingto develop data regarding groundwater and surface water interaction in theMiddle Rio Grande Valley and has since included support for modeldevelopment and maintenance in its Program funding priorities. Significantprogress in the capability of the URGWOM model has been made since thecompletion of the Preliminary Analysis.

J. Upper Rio Grande Basin Water Operations Review

The Upper Rio Grande Basin Water Operations (URGWOPS)Review is a separate project that utilizes the URGWOM model to conducta comprehensive system-wide review of water operations activities that areconducted under the existing legal authorities of the joint lead agencies: theCorps, BOR, and the New Mexico Interstate Stream Commission (ISC).These water operations consist primarily of storage and release of water atreservoirs, changing the channel capacity criteria, extension of waivers24 atHeron, and operation of the Low Flow Conveyance Channel. In accordancewith the National Environmental Policy Act (NEPA), a Draft EnvironmentalImpact Statement (EIS) was written utilizing the URGWOPS review as thebasis of the Middle Rio Grande Valley's water operations. The Draft EISevaluates environmental, economic, and social effects of alternative wateroperations at federally operated facilities in the Upper Rio Grande Basinwithin existing legislative authorities.2s The Preliminary Analysis plannedto look at potential scenarios beyond what is already authorized by existinglegislation. Thus, the work was distinct from the ongoing work in theURGWOPS Review.

24. Water in storage in Heron Reservoir owned by SJC contractors must be evacuated

every year by December 31. The BOR has a practice of allowing temporary waivers of thisrequirement until April 30. Upper Rio Grande Water Operations Model, Rules Documentation,at RULES-4 (June2005 Draft), availableathttp://www.spa.usace.army.mil/urgwom/trcdocs/jun2005/Rules% 20Description%200une,%202005)%20(RULES).pdf.

25. BuREAu OF RECLAMATION, U.S. ARMY CORPS OF ENG'RS & N.M. INTERSTATE STREAM

COMM'N, UPPER Rio GRANDE WATER OPERATIONS REVIEW DRAFT ENVIRONMENTAL IMPACT

STATEMENT (2006), available at http://www.spa.usace.army.mil/urgwops/drafteis.htm.

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III. PRELIMINARY ANALYSIS

A. Summary of Process

The Preliminary Analysis project began in January 2004 whenconfidential negotiations sponsored by New Mexico Governor BillRichardson between parties to Rio Grande Silvery Minnow v. Keys26 had cometo a standstill. As a member of WAM representing the University of NewMexico, the Utton Center suggested that one approach to watermanagement issues might be to develop a variety of water managementalternatives and then evaluate these by using an agreed-upon modelingtool. This process would provide a preliminary assessment of whichstrategies provided benefits to the. system and which did not. Then thefocus could be narrowed to look at the most promising alternatives in moredetail. It was anticipated that this work would lead to a project whereProgram funding2 7 could be used to evaluate water management strategies- minimizing the supplemental water needs for the ESA without impairingwater rights. The Utton Center was tasked with developing a scope of workthat outlined an approach and this scope of work was modified by WAMas the discussion progressed.

WAM held meetings to formulate the Preliminary Analysis andvarious models were considered. There was a broad discussion of issuesand possibilities, and many approaches were considered. A suggestion wasmade, for example, to examine a South African process where teams hadformed and each created its own planning vision for the future. Thedifferent visions were then available for the parties to negotiate long-rangesolutions. As applied to the Preliminary Analysis, the idea was to formgroups, each with its own view of water management practices for theMiddle Rio Grande. These groups would develop separate scenarios andagree on an objective model to evaluate the hydrologic implications of eachscenario. At this stage, a wide range of river management strategies(including irrigation efficiencies, voluntary agricultural forebearance,riparian restoration, and others) were under consideration.

It became apparent early on that it was necessary to know thecapabilities of various models in order to decide how to proceed. Thediscussion turned to gaining a better understanding of the models availablefor use in the Middle Rio Grande and a list was compiled of potential tools,including HEC-RAS, a geographic information system based river flow

26. 356 F. Supp. 2d 1222 (D.N.M. 2002).27. The Preliminary Analysis, as was true for most Program subcommittee work, was

unfunded. It was undertaken by agency personnel and other interest groups in addition toregular job duties or on a volunteer basis.

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model being used by the University of New Mexico; the National HeritageInstitute Rio Grande/ Rio Bravo Basin Model; the Upper Rio Grande WaterOperations Model; and the Sandia National Laboratories System DynamicsModel for the Middle Rio Grande. When the Utton Center researched themodels, many WAM members who were familiar with these and other toolswere able to provide expertise to help evaluate them. WAM discussed themodels and whether they could fulfill the needs of the project and focusedon URGWOM as the most highly developed modeling tool at that time. TheWAM technical issues subcommittee held several meetings with theURGWOM Technical Team (Tech Team), a group of hydrologic modelingexperts who were assigned to develop and improve the URGWOM model.

One concern was whether URGWOM would be useful to modelriver operations (such as agricultural diversions and returns) beyondreservoir operations. The Tech Team also knew that URGWOM had limitedcapabilities to meet specific daily flow targets as required by the BiologicalOpinion in effect for the silvery minnow at that time.2 8 However, there wereno alternative models available that could test a variety of water operationsscenarios. For this reason, the project became focused on modeling reservoirstorage opportunities. URGWOM was the best tool for this work and WAMhad several joint meetings with the Tech Team to develop the PreliminaryAnalysis approach.

The Tech Team asked that WAM prepare specific scenarios to bemodeled so that they could assess how to proceed. It was understood thatfunding might be needed in order to make the rules adjustments29 inURGWOM to be able to test scenarios if the scenarios went beyondcurrently authorized operations. There were different viewpoints on howto approach the Preliminary Analysis. Initially, the Tech Team wanted theproject to look at all stakeholder interests, not just endangered speciesneeds. They suggested that WAM obtain broad agreement on howownership of storage rights, water rights, and releases would be modeled.WAM felt this was beyond what was achievable and necessary at this verypreliminary stage. Others were not convinced that any scenarios should beconsidered that went beyond the legal authorizations for each reservoir.Most participants agreed, however, that this was the main point of theexercise, since the URGWOPS Review was already examining flexibilitiesunder existing authorities.

Some participants were concerned that trying to model improvedstorage without defining the use of the water for endangered species did

28. URGWOM's ability to model specific target flows has been significantly enhancedsince 2004.

29. The ruleset for URGWOM consists of the Tech Team's interpretation of operationalpolicy, regulations, preferences, and other decision-making logic.

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not support Program goals. But WAM concluded that, as a first step, thePreliminary Analysis should focus on finding management strategies tomaximize water supply. Subsequent phases could include stakeholders indiscussions about how to manage any additional water and, later, thenegotiation of some portion of the water for instream flows or for otherProgram habitat-related needs.

During this time, WAM was also working on other related matters,such as estimating the projected Program water demand (the amount ofsupplemental water needed to meet the terms of the Biological Opinion for10 years under varying hydrologic conditions) and evaluating whether theflow targets of the Biological Opinion were realistic. WAM decided not toreexamine the flow targets as part of the Preliminary Analysis, but insteadaccepted them as a given. Article VII of the Rio Grande Compact, limitingNew Mexico's ability to store runoff, was also a topic because it was ineffect at that time and projected to be in effect for most of the ten-yearBiological Opinion. Some participants advocated that WAM should focusonly on short-term water management concerns due to the exigencies of thedrought. WAM members finally decided that long-term storage flexibilityshould be one component of its work.

At this point, WAM made another important decision: any scenarioto be modeled in the Preliminary Analysis would be chosen by consensus.Before proceeding with any modeling work, all WAM members had toagree to the scenario and WAM would also obtain the approval of theProgram's Steering Committee. This agreement, although probablynecessary to keep the project moving forward, ultimately prevented thePreliminary Analysis from looking at a wide range of viable solutions. TheUtton Center tried to focus the project on the physical system at this stage,hoping stakeholders would see advantages in exploring whetherURGWOM could show probable water gains by testing changed operations.But it became clear as alternatives were considered that each posedproblems to one stakeholder or another and it was not possible to achieveconsensus. Even though WAM was not able to proceed with modeling atthat time, the alternatives developed and discussed were informative.

B. The Alternatives

All parties were invited to suggest scenarios that might optimizewater supply in the Middle Rio Grande Valley or provide water in thesystem when needed for the silvery minnow. Each scenario had to addressCompact delivery requirements. Several scenarios were brought up andquickly dropped because of immediate and strong opposition by astakeholder. The discussion of these alternatives was short and cursory.Other scenarios were discussed at length and in detail before oppositionsurfaced. Here is a summary of the alternatives WAM considered.

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1. Reauthorization or Re-regulation of Cochiti Lake

Discussion of Cochiti Lake surfaced immediately, but it was briefand the proposals were quickly dropped because the Pueblo de Cochiti wasnot ready to discuss various operations of the lake. Many participants wereinterested in the potential of modeling changed reservoir storage operationsat Cochiti. Of particular interest was a proposal to model limited storage ofnative water in Cochiti to smooth releases from El Vado when summerthunderstorms occur below the Otowi Gage. This would preserve nativewater when releases have been made from El Vado to meet irrigationdemand and a thunderstorm in the Middle Rio Grande Valley obviates theneed for the water. The released water could be trapped in Cochiti andpossibly used subsequently for irrigation, thereby potentially decreasing theneed for supplemental water for the Program. Another proposal was tomodel the creation of a native water pool to be managed for the Programto meet the obligations of the Rio Grande Compact. The concept was toreplace the San Juan-Chama pool at Cochiti. Significant detail waspresented on this alternative.

The Utton Center suggested that there be no discussion of CochitiLake without concurrence of Cochiti Pueblo due to the sensitivity of theseissues to the Pueblo.3 During the summer of 2004 there were indicationsthat the Pueblo was interested in discussing the potential benefits of variousoperations of the Lake (in particular, the possibility of storing prior andparamount water of the Six Middle Rio Grande Pueblos). The Utton Centercontacted the Pueblo on behalf of WAM to determine whether they wereinterested in working with the Program to model any scenarios at Cochiti.A letter was directed to the Governor requesting a meeting to discusswhether there was an opportunity to model scenarios that would providebeneficial information to both the Pueblo (as input into the baseline studyunderway with the Corps) and to the Preliminary Analysis. After learningthat the Pueblo was not ready to discuss the lake with regional stakeholdersuntil the completion of the baseline study, WAM put this discussion onhold.

2. Rio Grande Project Storage

The New Mexico Interstate Stream Commission (ISC) opposed anyconsideration of modeling alternative storage strategies for Rio Grande

30. A discussion of Cochiti had taken place in the Collaborative Program in 2002 andrepresentatives of the Pueblo came to the Steering Committee and voiced objection to anyconsideration of re-operation or reauthorization of Cochiti pending completion of a baselinestudy to be conducted by the Pueblo in cooperation with the Corps. The baseline study is stillin progress and will evaluate the potential impacts of a range of water management optionsat Cochiti Lake.

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Project water.31 This position was not discussed in detail but was most likelyrelated to the ISC's ongoing dialogue with Texas about relinquishments ofNew Mexico credit water and other Rio Grande Compact-related matters.

3. Closed Basin

A proposal was made to evaluate the timing of the delivery ofwater from the San Luis Closed Basin Project in Colorado. The idea was towork with the BOR and Colorado to model increased water deliveriesduring July, August, September, and October. WAM was reminded that theSteering Committee requested that water sources from within Colorado notbe considered to meet Collaborative Program needs. A commitment hadbeen made on the part of the State of New Mexico not to seek contributionsto the Program from Colorado. There was correspondence from theDivision Engineer in Alamosa, Colorado to this effect, and he forwarded itto WAM upon learning of this proposal.

4. Agricultural Forbearance

Modeling an assumed level of voluntary agricultural forbearancein the MRGCD was proposed where farmers with water rights couldvoluntarily agree not to use their water in certain circumstances -usually

during a projected drought year - in exchange for compensation. Modelingof this scenario was opposed by the MRGCD for several reasons. First, thescenario was drafted to model a five-percent MRGCD demand reduction,and although it contemplated compensation to irrigators who wouldvoluntarily forebear, the MRGCD characterized it as an arbitrary reductionin MRGCD water supply.

Because a feasibility study of forbearance was in progress, MRGCDstaff felt that any further investigation of forbearance prior to completionof the study would be premature. The MRGCD also maintained that itssystem has a fixed volume of losses depending upon flow, time of year, andother factors, so that modeling a percentage demand reduction would notaccurately translate into additional water in reservoirs. The MRGCD alsostated that the water flowing through its system does not belong to theMRGCD, but rather to the individual landowners. Finally, the MRGCD feltthat Middle Rio Grande Valley gains and losses were not refinedsufficiently in URGWOM to model a forbearance alternative. For thesereasons this alternative was dropped pending the results of the forbearancefeasibility study.32

31. Rio Grande Project water is water delivered to Elephant Butte and Caballo reservoirsfor use in southern New Mexico, Texas, and Mexico.

32. As of February 2007, the Program continues to struggle with whether a voluntarycompensated agricultural forbearance (or leasing) program in the MRGCD is feasible.

Summer 20071


5. Abiquiu Reservoir

Two of the scenarios that were discussed in detail concernedAbiquiu Reservoir. Under one scenario, Abiquiu Reservoir operationswould be modeled to retain water in Abiquiu in lieu of release to ElephantButte Reservoir in May or June. Storage of native water would take place inunused City of Albuquerque storage space.

Currently, when the inflow to Abiquiu Reservoir exceedsdownstream channel capacity, the water is stored but released by July first.However, after July first, when the natural flow at Otowi gage falls below1,500 cfs, the Corps is prohibited from releasing flood waters untilNovember first and must fully release all flood waters by March 31 of thefollowing year. The release of the carryover flood water in storage isnormally set at a uniform rate. Releases in May and June cause higher lossrates through the Middle Rio Grande Valley and higher evaporation ratesif the water is stored in Elephant Butte Reservoir. This scenario looked atstoring compact delivery water and holding the water until November first.Channel losses, compact deliveries, peak flows in the Middle Rio GrandeValley, and reservoir losses would be compared to determine impacts andbenefits.

Holding water until November first raised concerns about browntrout spawning and fishery habitat in the Rio Chama below Abiquiu Dam.Several options were proposed to address this concern. One would be toevacuate storage between November first and December 25 at a uniformrate rather than delivering all the water in late December, as had been donein the past. The second would be to evacuate the storage beginningNovember first through March first. At all times the release rate fromAbiquiu Reservoir during the irrigation season (at times when Abiquiuwould be storing) would be set in accordance with MRGCD demand andother demands downstream (such as Biological Opinion requirements) atCochiti Dam, less mainstream flow. No storage would take place ifdownstream demands were not being met. The irrigation demand wouldbe set at the 2004 demand, as provided by the MRGCD.

Another proposed scenario for Abiquiu Reservoir was based onretaining water in Abiquiu when it was not needed for delivery to ElephantButte to meet Compact deliveries. The modeling time frame was to be a 40-year period, with the beginning condition an Article VII year, replicatingthe current drought cycle. After that, the model would utilize the sequencethat URGWOPS uses, which is a random sequence of wet, average, and dryyears. The alternative was structured to retain water in Abiquiu "if andwhen" storage space was not needed by the City of Albuquerque and its

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subcontractors.33 The expectation was that there would be significantly lessevaporative loss by storing the water in Abiquiu as opposed to deliveringit to Elephant Butte. The first phase of this analysis would quantify thepotential gains in water supply over a 40-year period for the Middle RioGrande Valley based upon this revised operation. A subsequent phasewould be required to study how to manage this water.

During the course of WAM's discussions, the City of Albuquerqueobjected to pursuing any studies that would change the operations ofAbiquiu. According to the City, the Program placed too much emphasis onlooking to City-controlled facilities for water supply and managementsolutions and did not seek solutions from the other involved parties. TheCity explained that it would be more amenable to working with theProgram on alternatives at Abiquiu if other entities would agree to modelchanged reservoir operations in other reservoirs. In particular, the Citybelieves Cochiti Reservoir offers great potential.

Because WAM could not achieve consensus on modeling changedoperations at Abiquiu, it was not pursued.3' As alternatives at Abiquiu areconsidered in the future, the following factors will be required in order toimplement changes in how the reservoir is managed: agreement onproposed operational revisions and management of any conserved water,approval of the Rio Grande Compact Commission, a detailedenvironmental analysis, a permit to store water from the State of NewMexico, and legal agreements for water storage.

6. Heron Reservoir

WAM also discussed operations at Heron Reservoir in order todetermine the best place to store Program-acquired supplemental water(San Juan-Chama water acquired from willing lessors). WAM hoped toevaluate the ability to carry over San Juan-Chama water in Heron insteadof being forced to move the water to Abiquiu or El Vado if not needed in aparticular year.

One alternative involved modeling (as a sample pool) storage of theCity of Santa Fe's San Juan-Chama water assuming delivery in 2003 hadbeen taken at Heron Reservoir instead of moving the water to Abiquiu. Acomparison of two different ways of managing the City of Santa Fe water

33. The City holds easements on the land where the reservoir sits and controls thereservoir storage space via a storage contract with the Corps. The City of Albuquerque waterutility is now the Albuquerque-Bernalillo County Water Utility Authority.

34. Since the date of the Preliminary Analysis, the City has agreed to work with theenvironmental Plaintiffs in Rio Grande Silvery Minnow v. Keys to create space for a 30,000 acre-foot environmental pool at Abiquiu; the URGWOM Tech Team is working under a contractwith the Program on Abiquiu alternatives; and, as of February, 2007, the URGWOPS Draft EISincludes alternatives at Abiquiu within existing authorities.

Summer 2007]


would provide an example for quantifying the difference in evaporativeloss in storing the water in Heron Reservoir rather than moving it toAbiquiu. Currently, SJC water contractors must take delivery of contractedwater in storage at Heron Reservoir by the end of the year, either by use,sale, or by contracts for storage elsewhere. Ownership of contracted waterthat is not withdrawn or transferred from Heron Reservoir by December 31reverts to Heron as part of the project water supply. In the past, the BORhad negotiated temporary waivers with contractors to allow carryover untilApril 30 in order to provide release rates on the Rio Chama to enhance thefishery between El Vado and Abiquiu Reservoirs during the winter andprovide flexibility in managing river flows. Temporary waivers haveextended beyond April 30.

The first Heron alternative would require significant rules changesto the URGWOM model. This alternative is more complicated than Abiquiudue to the connection between the authorizing legislation for the San Juan-Chama Project and the compacts on the Colorado River. The City ofAlbuquerque argued that any modification of the "no carryover" provisionin the City's San Juan-Chama Project water service contract with BOR fordelivery of water at the Heron Reservoir outlet works would require anamendment to its contract. The City of Albuquerque did not supportmodeling this scenario because it did not want to amend its contract.

A second Heron alternative would have evaluated the capture ofnative Chama flows in Heron. These flows are currently bypassed becauseHeron Reservoir is only authorized for storage of imported SJC water. Thepotential magnitude of native inflow to Heron is relatively small, about16,000 acre-feet average per year over the past 20 years.35 Potentialoperational benefits are minor. The legislative authority to store nativewater in Heron does not currently exist. Modeling this alternative wouldrequire a significant rules change in URGWOM. A new set of hypotheticalrules would need to be developed because Heron currently only hasaccounts for contractors' San Juan-Chama water.

Changes to Heron's operations would be difficult for many reasons.Ownership of Rio Grande water rights and the right to store would berequired in order to store native water in Heron Reservoir. The acquisitionof Rio Grande or Rio Chama water rights would be expensive and, unlessthe water rights are senior rights, storage in Heron would not be allowedunless all downstream water rights had been satisfied. An amendment ofthe Heron contract would be required, and as previously discussed, a majorstakeholder (the City of Albuquerque) was opposed to seekingcongressional changes to the authorization of Heron.

35. U.S. BUREAU OF RECLAMATION, WATER ACCOUNTING REPORT TO THE Rio GRANDECOMPACT COMMISSION ENGINEER ADVISORS (1984-2003).

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7. El Vado Reservoir

Proposals regarding El Vado were not very fully developed sincethe preliminary ideas involved relocating the prior and paramount waterstored for the Middle Rio Grande Pueblos from El Vado to either Cochiti orAbiquiu. Because discussion of those two reservoirs was taken off the table,discussion of El Vado was fruitless. During Article VII or in drought years,changes at El Vado might be helpful. When Article VII is not in effect, ElVado fills frequently and there is not room in the reservoir for CollaborativeProgram water storage; nevertheless, operation of El Vado should beevaluated in conjunction with alternatives at the other reservoirs to see ifimprovements can be made.

IV. CONCLUSION

Much progress has been made on water management and storagein the Middle Rio Grande Valley since litigation concerning endangeredspecies began in 1999. The Collaborative Program's Preliminary Analysis,concluded in 2005, while not resulting in model runs, illustrated the varietyof options, the challenges each faces, and the relative positions of theparties. Talks between the stakeholders and agencies about reservoirstorage flexibility have continued and a funded Program project for theURGWOM Tech Team to work with WAM on modeling is underway.Meanwhile the Draft Environmental Impact Statement (EIS) for the UpperRio Grande Water Operations Review was completed and was still underreview as of early 2007. The EIS may provide new directions to look beyondexisting authorities.

The environmental Plaintiffs in Rio Grande Silvery Minnow v. Keyssettled their suit against the City of Albuquerque, and Abiquiu storage wasincluded as a component of the settlement. The arrangements for how thestorage space will be operated have not been developed, and WAM maycontinue to have some involvement in this issue through the modelingproject with the URGWOM Tech Team. The Preliminary Analysis led theUtton Center, in conjunction with the Natural Resources Journal, to sponsora Rio Grande Reservoir Symposium in 2006, where there were severalgroundbreaking presentations on the reservoirs. 6 In short, the work of theWAM on the Preliminary Analysis was important to furthering the dialogueon reservoir issues.

36. See The Utton Transboundary Resources Center, NRJ-Utton Center Rio GrandeReservoir Symposium, http://uttoncenter.unm.edu/Reservoir-Symposium.html (last visitedJuly 25, 2007).

Summer 2007]


Solutions to the water supply problems for the Middle Rio Grandeand its endangered species will need to come from a variety of sources andwater management strategies. All possibilities should be considered,including changed reservoir operations.

In a drought cycle, it is hard to work on long-range scenarios thatmight only reap benefits during wet cycles. The reality of long-term climatechange on top of the highly variable seasonal supply adds to New Mexico'swater management challenges. But, the Middle Rio Grande Valley must beprepared for wet years when they come.

In 1988, when meetings were held on the Reevaluation of the RioGrande Operating Plan, there was excess water in the Rio Grande systemand every reservoir in the system was at the limit of its legally authorizedstorage - Elephant Butte Reservoir was overflowing and flooding occurredbelow El Paso. Eight of the ten years preceding 1988 experienced higherthan normal runoff and all authorized conservation space in the basin'sreservoirs was filled. It would have been advantageous to be able to useflood space for conservation purposes, rather than being forced to releasewater as required by law.

Early in the debates about how to address the water needs of thesilvery minnow, six collaborating agencies prepared a White Paperoutlining recommended management options.37 The Program and WAMdeserve credit for pursuing and continuing to explore many of theseoptions. It is interesting to note that in the White Paper operational andinstitutional changes to reservoirs were considered a high priority:

Attention should first be directed towards more immediatelyattainable actions such as upstream water managementoptions.. .and efforts should be initiated to make institutionalchanges as may be deemed appropriate to help accommodateboth water users and the silvery minnow in the long-term.Where additional studies are deemed required to fullyevaluate a potential action, the agencies and entities repre-sented in the preparation of this paper should cooperate insecuring the necessary resources to complete such studiespromptly. 8

37. Jeff Whitney, U.S. Fish & Wildlife Service; Rob Leutheuser, U.S. Bureau ofReclamation; Dick Kreiner, U.S. Army Corps of Engineers; Rich Barrios, U.S. Bureau ofReclamation; John Whipple, N.M. Interstate Stream Commission; Subhas Shah, Middle RioGrande Conservancy District; & Gary Daves, City of Albuquerque, Water Management Strategyfor the Middle Rio Grande Valley, in Preliminary Reservoir Storage Modeling Analysis (AttachmentD), in FINAL REPORT, supra note 10.

38. Id. at D-29.

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Summer 2007] MODELING RESERVOIR STORAGE 673

Although the Preliminary Analysis was intended to be an objectiveand technical assessment of viable approaches to complex water manage-ment issues, it is obvious that the discussion ultimately turned on otherconsiderations - social, political, and legal. Some criticized WAM for takingon such a contentious issue.

. In the long run, the river must have a sustainable supply, not justfor endangered species, but for human well-being and survival.Stakeholders in the Middle Rio Grande Valley must work together tooptimize the use of the Rio Grande reservoirs: meet the needs of waterusers, make New Mexico's required Compact deliveries, and meet the waterrequirements for the endangered species. Objective, scientifically soundanalysis of alternative management strategies is the place to start.

Documents

Modeling Reservoir Storage Scenarios by Consensus